tree a3c568b34226152a8f825c7ce1cff8a8bf1a20c2
parent 42536b9f9ce38b07ac213c5f4550301f9a0d251d
author Russell King <rmk+kernel@arm.linux.org.uk> 1373368489 +0100
committer Russell King <rmk+kernel@arm.linux.org.uk> 1383230961 +0000

ARM: DMA-API: better handing of DMA masks for coherent allocations

We need to start treating DMA masks as something which is specific to
the bus that the device resides on, otherwise we're going to hit all
sorts of nasty issues with LPAE and 32-bit DMA controllers in >32-bit
systems, where memory is offset from PFN 0.

In order to start doing this, we convert the DMA mask to a PFN using
the device specific dma_to_pfn() macro.  This is the reverse of the
pfn_to_dma() macro which is used to get the DMA address for the device.

This gives us a PFN mask, which we can then check against the PFN
limit of the DMA zone.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>